In the production of both walk-in and reach-in commercial refrigerators it is common practice to construct the cabinets with a roof aperture and to utilise drop-in refrigeration units. This practice eliminates the need for cabinet makers to employ costly specialised labour for the installation of individual refrigeration components. It is customary with such drop-in units to include a temperature insulating plug for positioning within the cabinet aperture and which mounts the compressor and condenser above the plug and the evaporator below. To allow for mounting of the evaporator and to achieve a good air circulatory pattern within the cabinet the entire unit protrudes somewhat into the cabinet with consequent loss of storage space.